Esters of acyloxycarboxylic acids have long been known for a wide variety of applications. Thus, for example, U.S. Pat. No. 2,464,992, issued Mar. 22, 1949, inventors Rehberg et al. teaches several methods for obtaining acyloxycarboxylic acid esters from starting materials such as glycolic or lactic acid with the esters useful as solvents, plasticizers, insecticides, insect repellents and chemical intermediates. An acyloxy acetic acid is disclosed as imparting excellent rust preventing characteristics to hydrocarbon mineral oils by U.S. Pat. No. 2,659,697, issued Nov. 17, 1953, inventor Wayo.
More recently, U.S. Pat. No. 4,085,277, issued Apr. 18, 1978, inventor Harada, discloses preparation of 2-cinnamoyloxyacetic acid as a starting compound in the preparation of a cephaloaporanic acid derivative possessing antibacterial activity.
Pending application Ser. No. 928,070, entitled "Glycolate Ester Peracid Precursors", filed Nov. 6, 1986, now U.S. Pat. No. 4,778,618 inventors Fong et al., of common assignment herewith, discloses compounds termed alkanoyloxyperacetic acid which are generated in situ when precursors are placed in aqueous solution with a source of hydrogen peroxide. These precursors are readily prepared from the acyloxycarboxylic acids synthesized by the present invention.
U.S. Pat. No. 2,503,699, issued Apr. 11, 1950, inventors Adelson et al., discloses the reaction of 1.9 equivalents acetyl chloride with 1.0 equivalent glycolic acid in a single reaction vessel to obtain acetylglycolic acid, which was isolated by evaporating excess actyl chloride. However, the inventors report that the reaction was violent and evolved much hydrochloric acid. Acid chloride removal by evaporation to isolate product is not appropriate for longer chain acid chlorides.
U.S. Pat. No. 4,036,984 discloses adding various chlorides slowly under ice cooling into mixtures of various acids or alcohols with the mixtures including pyridine. However, when these known techniques are applied to the synthesis of acyloxycarboxylic acids such as, for example, octanoyloxyacetic acid, isolated yields of only about 40% to about 45% are obtained.